Advanced numerical models for elastomeric and sliding isolators for nuclear structures Manish Kumar2, Ph.D. Candidates Andrew Whi>aker, Ph.D., S.E. Director, MCEER Michael ConstanCnou, Ph.D. Professor University at Buffalo June 18 and 19, 2013 SILER InternaConal Workshop, Rome Acknowledgments •
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US Nuclear Regulatory Commission Dr. Annie Kammerer, USNRC Dr. Robert Budnitz, LBNL LBNL oversight commi>ee –  Nilesh Chokshi –  Antonio Godoy –  James Johnson –  Robert Kennedy –  Don Moore –  Jon Stewart June 18 and 19, 2013 SILER InternaConal Workshop, Rome Outline •  Framework for advanced models –  All types of surface-­‐mounted nuclear structures –  United States Nuclear Regulatory Commission •
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NTTF and extended design basis Seismic isolaCon NUREG Analyzability USNRC ESSI simulator –  ASCE 4 (Department of Energy) •  Beyond design basis •  SecCon 7.7 •  Analyzability •  QualificaCon of new isolators and isolaCon systems •  Advanced models for elastomeric and sliding isolators •  On-­‐going studies June 18 and 19, 2013 SILER InternaConal Workshop, Rome QualificaCon of new isolators •  Building a body of knowledge and confidence in performance and manufacture •
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–  Compliance with NQA-­‐1 or similar –  Manufacturer-­‐specific TesCng of full-­‐scale specimens V&V models of isolators Changes in material properCes System-­‐level tesCng V&V tools and codes to predict system response Deployment of isolaCon system June 18 and 19, 2013 SILER InternaConal Workshop, Rome VerificaCon and validaCon ASME NQA-1–2012
(Revision of ASME NQA-1–2008)
Quality Assurance
Requirements for
Nuclear Facility
Applications
A N A M E R I C A N N AT I O N A L STA N DA R D
Copyright c 2013 by the American Society of Mechanical Engineers.
No reproduction may be made of this material without written consent of ASME.
June 18 and 19, 2013 SILER InternaConal Workshop, Rome VerificaCon •  Process of determining that a computaConal model accurately represents the underlying mathemaCcal model and its soluCon (ASME) •  Code verificaCon –  Numerical code verificaCon •  Code to code comparison –  Sobware quality assurance •  SoluCon verificaCon June 18 and 19, 2013 SILER InternaConal Workshop, Rome ValidaCon •  Process of determining the degree to which a model is an accurate representaCon of the real world from the perspecCve of the intended uses of the model (ASME) •  Experimental validaCon –  Results of verified computaConal model compared with experimental data June 18 and 19, 2013 SILER InternaConal Workshop, Rome Plan for verificaCon and validaCon June 18 and 19, 2013 SILER InternaConal Workshop, Rome Isolator displacements •
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Isolated period (Kd) of 2 seconds, Qd = 0.06W BDBE = 150% DBE in DOE space EDBE = max (167% DBE, UHS at MAFE = 10-­‐5) in NRC space North Anna, EUS, hard rock –  50%-­‐ile DBE = 25 mm –  99%-­‐ile DBE = 40 mm –  90%-­‐ile BDBE = 50 mm •  Vogtle, CEUS, soil, Ts = 1.6 seconds –  50%-­‐ile DBE = 250 mm –  99%-­‐ile DBE = 415 mm –  90%-­‐ile BDBE = 625 mm •  Diablo Canyon, WUS, rock –  50%-­‐ile DBE = 475 mm –  99%-­‐ile DBE = 765 mm –  90%-­‐ile BDBE = 990 mm June 19 and 20, 2013 SILER InternaConal Workshop, Rome Numerical models of isolators •  Elastomeric isolators –  Advanced models –  OpenSees and ABAQUS June 18 and 19, 2013 SILER InternaConal Workshop, Rome Advanced models Advanced models •  User elements in OpenSees and ABAQUS –  ElastomericX for LDR and LeadRubberX for LR bearing •  2 Node, 12 DOF, 3D discrete element June 18 and 19, 2013 SILER InternaConal Workshop, Rome Advanced models •  New model in axial direcCon •  Bouc-­‐Wen and plasCcity models in shear VerCcal (axial) direcCon June 18 and 19, 2013 Horizontal (shear) direcCon SILER InternaConal Workshop, Rome Advanced models Proper&es
3DBASIS
SAP2000 PERFORM3D
LSDYNA
ABAQUS
OpenSees
New
Coupled horizontal direc&ons
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Coupled horizontal and ver&cal direc&ons
No
No
No
No
No
No
Yes
Different tensile and compressive s&ffness
No
No
Yes
Yes
Yes
Yes
Yes
Nonlinear tensile behavior
No
No
No
No
Yes
Yes
Yes
Cavita&on and post-­‐
cavita&on
No
No
No
No
No
No
Yes
Nonlinear compressive behavior
No
No
No
No
Yes
Yes
Yes
Varying buckling capacity
No
No
No
No
No
No
Yes
Hea&ng of lead core
No
No
No
No
No
No
Yes
ElastomericX V&V Iwabe et al. (2000) June 18 and 19, 2013 Warn and Whi>aker (2006) SILER InternaConal Workshop, Rome LeadRubberX V&V June 18 and 19, 2013 SILER InternaConal Workshop, Rome LeadRubberX V&V June 19 and 20, 2013 SILER InternaConal Workshop, Rome Summary: elastomeric •  New computaConal models to capture most behaviors of elastomeric bearings expected under beyond design basis earthquake shaking –  SubstanCal extension of exisCng capabiliCes •  Code-­‐to-­‐code verificaCon, OpenSees and ABAQUS, shows good agreement •  CalibraCon with experimental data needed for some unknowns •  ValidaCon experiments to be performed –  16 bearings to be tested at UB June 18 and 19, 2013 SILER InternaConal Workshop, Rome Numerical models of isolators •  Spherical sliding bearing –  FricCon Pendulum •  Single concave –  Advanced models •  Pressure •  Velocity •  Temperature June 18 and 19, 2013 SILER InternaConal Workshop, Rome Advanced models HITEC (1998) Force-­‐displacement relaConship Post yield sCffness (K) CharacterisCc strength (Q) Coefficient of fricCon (µ) Velocity (v) June 18 and 19, 2013 Axial load (P) Temperature (T) SILER InternaConal Workshop, Rome Radius of curvature (R) Advanced models •  Reference coefficient of fricCon (µref) measured at –  Reference temperature, To = 20C –  Reference axial pressure, po –  High velocity, 200+ mm/s •  Pressure (p), temperature (T), velocity (v) Advanced models •  FricCon and 1) temperature, and 2) pressure –  µref = 0.06 at po = 50 MPa, To = 20C, v = 1000 mm/s Advanced models •  OpenSees ‘flatSliderBearing’ updated –  Coefficient of fricCon –  Lateral force –  Lateral sCffness •  Single FP bearing –  Sliding period = 3 s –  Reference coefficient of fricCon of 0.06 measured at a staCc axial pressure of 50 MPa –  Radius of contact area: 200 mm June 18 and 19, 2013 SILER InternaConal Workshop, Rome Advanced models •  Ground moCons for analysis –  30 sets of ground moCons for Diablo Canyon –  Scaled to match geomean spectra (H, V) Advanced models •  Alternate fricCon models –  Coulomb, µ=Coulomb –  Pressure dependent, µ=f(p) –  Temperature dependent, µ=f(T) –  Velocity dependent, µ=f(v) –  All dependencies, µ=f(p, T, v) •  Impact on displacement responses June 18 and 19, 2013 SILER InternaConal Workshop, Rome Advanced models •  Average fricCon over strong shaking duraCon Advanced models •  Force-­‐displacement response for GM30 Advanced models •  History of coefficient of fricCon for GM30 Advanced models •  Maximum displacement and temperature June 18 and 19, 2013 SILER InternaConal Workshop, Rome Summary: sliding •  Sliding period = 3 sec, staCc pressure = 50 MPa –  Median displacement •  Temperature effects most significant •  Pressure and velocity effects of secondary importance –  90+%-­‐ile displacements •  Impact of fricCon model not that important •  At lower staCc axial pressures, say 15-­‐25 MPa –  Temperature effect less important •  Scope of analysis being expanded •  VerificaCon and validaCon of fricCon model June 18 and 19, 2013 SILER InternaConal Workshop, Rome On-­‐going studies •  Sample model of NPP being developed –  EPRI supplied; based on WEC AP1000 –  Modeled in LS-­‐DYNA and OpenSees –  To be modeled in ESSI •  Earthquake analysis for mulCple sites –  DBE and Extended DBE (hazard at 10-­‐5 MAFE) –  IdenCfy what effects should be modeled –  Soil-­‐structure interacCon analysis •  Nonlinear Cme domain essenCal for soil sites •  Beyond design basis aircrab impact June 18 and 19, 2013 SILER InternaConal Workshop, Rome awhi>ak@buffalo.edu www.csee.buffalo.edu www.mceer.buffalo.edu June 18 and 19, 2013 SILER InternaConal Workshop, Rome